Title :
Abnormal conduction properties of ZnO varistor fabricated by 3-composition seed grain
Author :
Lee, Joon-Ung ; Jang, Kyung-Uk ; Wang, Jong-Bae ; Park, Yong-Pil ; Park, Choon-Bae
Author_Institution :
Dept. of Electr. Eng., Kwangwoon Univ., Seoul, South Korea
Abstract :
A method for making low-voltage ZnO varistors having extra large grain size with the contents of 3-composition seed grain is reported. The conduction mechanism for a non-ohmic ZnO varistor fabricated by the 3-composition seed grain method was investigated. The knee voltage and nonlinear coefficient α of a sample with 3-composition seed grain of 5 wt.% are 5 V and 18, respectively. The conduction mechanism is mainly governed by thermionic emission below the knee voltage and the field emission of the double Schottky model above the knee voltage. The activation energy and trap level of those regions are calculated to be about 0.367 and 0.513 eV, respectively. The conduction mechanism for the nonlinear region above the knee voltage can be analyzed by the Fowler-Nordheim tunneling effect. The barrier height of the model in this region is about 0.32 eV
Keywords :
II-VI semiconductors; ceramics; grain size; piezoelectric semiconductors; powder technology; sintering; tunnelling; varistors; zinc compounds; 3-composition seed grain; 30 to 120 C; Fowler-Nordheim tunneling effect; II-VI semiconductor; ZnO varistor; abnormal conduction properties; activation energy; conduction mechanism; double Schottky model; extra large grain size; fabrication; field emission; knee voltage; low-voltage; nonlinear coefficient; piezoelectric semiconductor; thermionic emission; trap level; Current measurement; Grain size; Knee; Low voltage; Microstructure; Powders; Temperature distribution; Temperature measurement; Varistors; Zinc oxide;
Conference_Titel :
Electrical Insulation and Dielectric Phenomena, 1992. Annual Report. Conference on
Conference_Location :
Victoria, BC
Print_ISBN :
0-7803-0565-5
DOI :
10.1109/CEIDP.1992.283163
